The present invention relates to an ornamental article comprising a multiplicity of gem objects interconnected by a string passing through holes defined in the gem objects. The present invention is applicable to annular ornamental articles such as a necklace, a pendant, a bracelet, a hair band, a string of beads, an anklet ring, and the like.
The term "gem objects" used throughout the specification means precious stones, semiprecious stones, pearls, pieces of coral, amber, tortoise shell, and ivory, synthetic stones, imitation stones, and precious metals.
The gem objects, when finished, are generally of a spherical shape or in the form of a particulate body or small mass having a spherical surface.
FIG. 7 of the accompanying drawings illustrates three spherical gem objects 1a, 1b, 1c having respective through holes through which a string 2 passes. Each of the gem objects has a radius r. The length L of the string 2 which is inserted in the three gem objects is therefore equal to 6r.
These strung gem objects are generally used as a necklace, for example, in an annular or arcuate form and worn by the user. When in use, the string 2 is subjected to a strong tensile force.
FIG. 8 shows the manner in which the three strung gem objects are used in an arcuate form. It is empirically known that the maximum angle through which adjacent two of the strung gem objects are angularly displaced, or the string is bent, when the chain of the gem objects flexes, is 45 degrees. This requires manufacturers of ornamental articles to thread the gem objects on the string so that they can withstand damaging stresses even when two adjacent gem objects are angularly displaced through 45 degrees. Stated otherwise, the strung gem objects are practically usable sufficiently if they can withstand stresses arising from bending through 45 degrees. However, there are some technical difficulties in meeting the above requirement.
More specifically, unless the string 2 is tensioned to an appropriate extent under the condition of FIG. 7, there are gaps formed between the gem objects 1a, 1b, 1c, making the overall chain unsightly and lowering its commercial value.
If the string 2 is kept under suitable tension in FIG. 7, the string 2 tends to be excessively tensioned and at times cut off or elongated when bent as shown in FIG. 8. The unduly tensioned string 2 imposes localized forces on ends of the hole of the gem object, with the result that the ends of the hole of the gem object are highly likely to be damaged especially when the gem objects are easily damageable pieces such as pearls. Therefore, the procedure for threading gem objects requires much skill on the part of the worker who assembles chains of gem objects. Furthermore, the string used is limited in terms of material and performance. Even if a chain of gem objects is assembled with the required degree of skill and a desired string, the string is still apt to rupture when the chain of gem objects is strongly bent over or caused to flex.
As disclosed is Japanese Utility Model Publication No. 57(1982)-60341, there is known an ornamental article design in which an elastomeric spacer is placed as a spring member between two adjacent gem objects. With this convention arrangement, when the chain of interconnected gem objects is bent over, the string on which the gem objects are threaded is excessively tensioned, and tends to be cut off or elongated. The gem objects are also prone to damage since undue localized forces are imposed on ends of the holes in the gem objects. More specifically, as shown in FIG. 10, two spherical gem objects 1a, 1b each of a radius r are interconnected by a string 2 with a flat spacer 9 of a thickness s being interposed between the gem objects 1a, 1b. While the string 2 remains straight as indicated by the solid line, the distance L between the centers of the two gem stones 1a, 1b is expressed by L=2r+s. When the string 2 is bent over as indicated by the dot-and-dash line, the distance L' between the centers of the gem stones 1a, 1b is expressed by L'=2r+s+2l, which is greater than the distance L by 2l. As a consequence, the string 2 is pulled under a force commensurate with 2l, and the reactive force produced by the string 2 acts on the gem objects.